An important and really essential part of many lighting systems is the electronic or electromagnetic element commonly referred to as the ballast. Ballasts are used in fluorescent fixtures, and others which require different voltage, current or frequency for operation than the normal 115 v 60 Hz line voltage provided by the standard United States lighting circuits. Also, low voltage, such as 12V lamps require a step-down transformer between the power outlet and the lamps serviced.
The ballast or the step-down transformer, hereinafter referred to as the ballast, usually constitutes a rather bulky, heavy part of the system as compared with the lamps and their fixtures. In the case of standard fluorescent fixtures, which are recessed into a ceiling, the ballasts are normally concealed within the lamp housing and do not present any mounting problems, but often are different to service or replace.
In the case of ornamental or internal fixtures, there is seldom sufficient room to mount the ballast in the fixture. Often the attractive appearance of the fixture would be sacrificed if the ballast were present in the fixture. Likewise, cooling of the ballast by air convection or other means is often a requirement, so mounting of a ballast near a heat-generating lamp or lamps is undesired.
In many cases, the mounting of lamp fixture, which uses a ballast near interior partitions, is often a requirement, and has been difficult to meet. One other challenge to the lighting designer and the installer is to provide a fixture design that is easy to install and service and that also allows electrical inspection without interfering with the installation.